The Refractive Index and Other Properties of Doped ZnO films

2003 ◽  
Vol 764 ◽  
Author(s):  
A. L. Cai ◽  
J. F. Muth ◽  
H. L. Porter ◽  
A. Kvit ◽  
J. Narayan

AbstractOrdinary and extraordinary indices of refraction, film thickness and waveguide mode information of zinc oxide, zinc oxide doped with nitrogen and zinc oxide doped with tellurium were measured by using a prism coupling waveguide technique. The films were grown on c-axis sapphire substrates by pulsed laser deposition (PLD). High accuracy waveguide measurements show that the ordinary and extraordinary indices of refraction of ZnO samples change with the introduction of nitrogen or tellurium. The densification of films with annealing could also be tracked with precision refractive index measurement. The crystal structure and the optical properties of the films were also characterized by using x-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM) and cathodoluminescence (CL).

1996 ◽  
Vol 449 ◽  
Author(s):  
A. J. Drehman ◽  
P. W. Yip

ABSTRACTUsing reactive rf sputtering, we have grown (0001) oriented ZnO films in situ on heated c-axis sapphire substrates, that are promising, particularly in terms of surface roughness, as buffer layers for the subsequent epitaxial growth of III-V nitride films. We compare the effects of on-axis and off-axis sputter geometries on the film epitaxy and smoothness. We also examined the effect of substrate temperature on the growth and smoothness and quality of the film. X-ray diffraction was used to verify the hexagonal ZnO phase, its c-axis orientation and, qualitatively, the degree of its epitaxy. Atomic Force Microscopy (AFM) was used to determine the ZnO growth morphology and roughness. Our best films, obtained by off-axis sputter deposition, have a surface roughness of less than 1 nm.


1999 ◽  
Vol 597 ◽  
Author(s):  
Judit G. Lisoni ◽  
M. Siegert ◽  
C. H. Lei ◽  
C. L. Jia ◽  
J. Schubert ◽  
...  

AbstractWithin our program to develop ferroelectric thin film optical waveguides, we have studied the growth of epitaxial waveguides BaTiO3 on r-plane sapphire substrates with a MgO buffer layer. The films were prepared by pulsed laser deposition (PLD). Their structural properties were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), Rutherford backscattering (RBS) in random and channeling (RBS-c) configuration and atomic force microscopy (AFM). They displayed good crystalline quality, characterized by an RBS-c minimum yield of about 4–6%, a full width at half maximum (FWHM) of the XRD rocking curve measurement of the BaTiO3(200) reflection of 0.32° and a rms roughness of 1.2 nm in a film of ∼ 1.0 μm thickness. The epitaxial relationship was found to be BaTiO3(100) // MgO(100) // A12O3(1102). The refractive index, the birefringence and the optical losses have been measured.


1997 ◽  
Vol 482 ◽  
Author(s):  
A. J. Drehman ◽  
S.-Q. Wang ◽  
P. W. Yip

AbstractUsing off-axis reactive rf sputtering, we have grown extremely smooth, nearly epitaxial, (001) oriented ZnO films on c-axis sapphire substrates. Atomic Force Microscopy was used to determine that these films are extremely smooth, having an rms roughness of only a few tenths of a nanometer. Based on high resolution x-ray diffraction (HXRD), the ZnO is highly oriented, with a rocking curve width of less than 400 arc seconds for the (006) diffraction peak, and only somewhat larger for the (112) reflection. HXRD Phi scans show that the ZnO (112) reflection is rotated in the a-b plane by 30 degrees from the sapphire (113) direction. These two measurements indicate excellent in-plane orientation. We are investigating the use of these buffer layers for subsequent GaN growth. Electrical resistivities of the films exceeded 100 kΩ-cm making ZnO a potential candidate as an insulating buffer layer.


Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 215
Author(s):  
Rajeev R. Kosireddy ◽  
Stephen T. Schaefer ◽  
Marko S. Milosavljevic ◽  
Shane R. Johnson

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.


1999 ◽  
Vol 597 ◽  
Author(s):  
M. Siegert ◽  
Judit G. Lisoni ◽  
C. H. Lei ◽  
A. Eckau ◽  
W. Zander ◽  
...  

AbstractIn the process of developing thin film electro-optical waveguides we investigated the influence of different substrates on the optical and structural properties of epitaxial BaTiO3 thin films. These films are grown by on-axis pulsed laser deposition (PLD) on MgO(100), MgAl2O4(100), SrTiO3(100) and MgO buffered A12O3(1102) substrates. The waveguide losses and the refractive indices were measured with a prism coupling setup. The optical data are correlated to the results of Rutherford backscattering spectrometry/ion channeling (RBS/C). X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). BaTiO3 films on MgO(100) substrates show planar waveguide losses of 3 dB/cm and ridge waveguide losses of 5 dB/cm at a wavelength of 633 nm.


2020 ◽  
Vol MA2020-02 (24) ◽  
pp. 1750-1750
Author(s):  
Andrea Quintero Colmenares ◽  
Patrice Gergaud ◽  
Jean-Michel Hartmann ◽  
Vincent Delaye ◽  
Nicolas Bernier ◽  
...  

2020 ◽  
Vol 307 ◽  
pp. 185-191
Author(s):  
Noor Syafiqah Samsi ◽  
N.A.S. Affendi ◽  
M.K. Yaakob ◽  
M.F.M. Taib ◽  
A. Lepit ◽  
...  

Graphene-Zinc Oxide (Gr-ZnO) nanocomposites films were successfully synthesized via facile electrodeposition method in an aqueous solution under Gr concentration conditions. Gr, as a highly conductive carbon, acts as an anchor for ZnO nanosheets and plays a substantial role in controlling the degree of dispersion of ZnO nanosheets onto indium-doped tin oxide (ITO) substrate to form Gr-ZnO nanocomposite. Atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM) analysis of Gr-ZnO nanocomposite samples confirmed that the presence of ZnO nanosheets with a high degree of dispersity and crystallinity which is well linked to the thin layer of Gr nanoparticle on ITO substrate. The surface roughness of the films found increased to ~270 nm on Gr-ZnO as compared to Gr ~44 nm and ZnO ~3 nm. Further, the x-ray diffraction spectroscopy (XRD) analysis showed the result is in good agreement with Raman spectroscopy study. The cyclic voltammetry (CV) of Gr-ZnO nanocomposite revealed that the effect of electron-hole recombination process was increased and the presence of Gr in ZnO photoanode provides the fastest redox reaction and hence offers the fastest electron transfer in photoanode.


1999 ◽  
Vol 583 ◽  
Author(s):  
Martin Schmidbauer ◽  
Thomas Wiebach ◽  
Helmut Raidt ◽  
Peter Schäfer ◽  
Michael hanke ◽  
...  

AbstractThe strain distribution inside and in the vicinity of coherently strained self-organized islands has been investigated by high-resolution x-ray diffraction (HRXRD). Finite element method (FEM) calculations were carried out in order to calculate the strain field, which was then used to simulate x-ray reciprocal space maps on the basis of kinematical scattering theory. For Si0 75Ge0.25 islands an abrupt increase in the Ge-concentration at about one third of the island height has been found. This behavior can be attributed to different nucleation stages during growth. Highly strained buried CdSe quantum dots (QDs) strongly influence the surrounding ZnSe matrix. From reciprocal space maps and FEM simulations we were able to estimate the shape and size of the islands. The results are in agreement with transmission electron microscopy (TEM) and UHV atomic force microscopy (AFM) data.


2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Nadezhda Markova ◽  
Olga Berezina ◽  
Nikolay Avdeev ◽  
Alexander Pergament

Indium-zinc oxide (IZO) nanofiber matrices are synthesized on SiO2-covered silicon substrates by the electrospinning method. The nanofibers’ dimensions, morphology, and crystalline structure are characterized by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The results of studying the electrical properties of nanofibers, as well as their sensitivity to UV radiation depending on the In-to-Zn concentration ratio, are presented. It is shown that the highest sensitivity to UV is observed at the indium content of about 50 atomic %. The photocurrent increment with respect to the dark current is more than 4 orders of magnitude. The response and recovery times are 60 and 500 sec, respectively. The results obtained suggest that IZO nanofibers can find application as UV sensors with improved characteristics.


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